Fiyr Shades lurk behind the silver door in the Mort'tonshade catacombs dungeon. They initially appear as very dark moving shadows on the ground and then rise from the depths to attack or retaliate. They are combat level 98 and their primary weakness is arrows. On occasion they have also been known to leave their catacombs to attack trekkers and ramblers in the town above their dark burial place. Their remains can be cremated with magic pyre logs, requiring a Firemaking level of 80. The Salve amulet and Salve amulet (e) work well on this shade which is very useful if shades are assigned for a Slayer task.

When encountered during a Trek, they are simply named 'Shade'. They still drop Fiyr remains when killed.

In the Trek or Ramble, if they manage to break the door or the player opens the door for them, they will say "Your time has come, _______." or " It is over!, _______."

For about a week after the release of the Evolution of Combat, these monsters retained their pre-EoC stats. This made them have high combat levels, with low life points and damage, and a weakness to crush. Their stats were changed to the levels they had in the combat beta with the release of the Ariane quests.